Operation Mind Switch
by Viv24
Summary: "Dear God, what is it like to be inside your funny, little brains. It must be so boring." Sherlock was about to find the answer to that question very soon. But what he did not expect were complications...
1. An Experiment

**Disclaimers: **I do not own any of the BBC Sherlock characters, nor am I making any profits of it.

**Rating:** T for mild vulgar language.

**A/N: **To those of you who stumbled upon this fic and planned on reading it, I just want to say thank you so much for giving it a chance. This is my first multiple chapter fic and I am planning on finishing it no matter what. I hope to publish one or two chapters each day and I expect that it will not be over 5,000 words. Reviews are gratefully appreciated and I apologize ahead of time for the usage of American vocabulary, for I am not too familiar with British English. Before this note gets too long, thanks again and happy reading!

**Note: **This is a Johnlock fic set in the first season somewhere after "The Blind Banker" and before "The Great Game".

* * *

**Operation Mind Switch**

"_Dear God, what is it like to be inside your funny, little brains. It must be so boring."_

The articulation, in which he had uttered just a mere few weeks ago, sat at the back of the consulting detective's brain, a subconscious thought at first, but slowly grew and manifested itself into a puzzle waiting to be solved, an inquiry waiting to be investigated, a question waiting to be answered. It was a throwaway line and hadn't meant much back then, other than an outspoken thought, but as it grew, the detective became more and more obsessed with it until finally, he decided to conduct a way to satisfy his urge:

_**an experiment**_

This would be Sherlock's two hundredth experiment and while he does not feel sentimental about digits, he was rather excited for this one. It would certainly be his riskiest experiment so far and he needed only two things: the_** independent variable **__and __a__** willing participant**__. _The latter was the easiest of the two to acquire, perhaps disregarding the "willing" portion, but Sherlock was not going to be bothered by that notion. As for the former, well, let's just say he liked challenges and another way to tick his brother off.


	2. The Willing Participant

"So tell me again what this is?" John stared uneasily at the pale amber liquid in his cup. It was a late evening in London and the living room of 221B Baker Street was very warm and homey. John was in the middle of a crime fiction novel when a pale blue cup appeared a few inches in front of his face.

"Tea, of course," said Sherlock simply, "Just the way you liked it, slightly brewed with two sucrose cubes."

"But I've never made tea in front of you, nor have I let you taste mine!" John stated, surprised.

"Well last week, you accidentally handed me your cup and judging by the color of the tea, I deduced that you don't pour milk to it and since there were small amounts of crystals on the kitchen table, you obviously added sugar. There were no particles left at the bottom of the cup, so the liquid must not have been filled with too much sugar, given the volume and time you handed it to me, as the saturated liquid will no longer dissolve it. Hence, two cubes." Sherlock replied with exaggerated patience.

_So he observed my tea too. Fantastic, _John thought sarcastically, but with a hint of actual amazement and slight flattery. A couple of months ago, he would have been completely blown away, but by this time, John was used to the astounding deductions and observations of the great Sherlock Holmes...almost. He brought the cup closer to his lips and took a quick sniff. There wasn't a particularly distinct aroma other than the usual Earl Gray, but as John tilted the cup slightly and took a sip, he noticed Sherlock had slightly shifted his position on the couch across him and was now watching intently.

"Did you perchance put anything, other than sugar, into my cuppa?" John frowned at the now curious detective.

"I'm not intending on poisoning you, if that's what you're asking," he replied.

"That's not what I meant," John's frown deepened as he stared into Sherlock's poker face and spoke tiredly.

They locked eyes for a moment.

"Well, if it will make you feel better, I'll have a cup of that tea myself with some sugar," Sherlock said finally. That did not make John feel better, but it did relieved him of some doubts. He watched Sherlock like a hawk as the man sauntered gracefully into the kitchen, poured himself a cup of tea from the same kettle and dropped two cubes of sugar from the same jar. He proceeded to the sofa, leaned back, and drank his tea leisurely. There was no telling what he was up to. His composure was flawless and he wore a cool expression that told John not to worry. But this was Sherlock we're talking about and John knew better than anyone, besides his brother of course, to just accept his word for it. However, he also knew that there was no way around him and all he could do was to trust the tight-lipped sleuth sitting calmly in front of him. _Damn_.

After staring warily for a minute, John decided that it was safe (_sort of_) for him to consumed the suspicious liquid in his cup, slightly cold now. The tea tasted a little funny, but John decided that it might have been the lack of experience Sherlock had for brewing tea. After all, it was John's job, by default. Besides, he was too tired now to listen to another word the detective had to say and excusing himself, he closed his book and went upstairs to his room for the night.

* * *

Sherlock peered up from his now emptied cup and watched as John shut the door with a slight _thud_. He then stood up and cleared away the dishes before turning off the lights and heading up to his room as well. He wanted to stay awake and observed the transformation, but he knew that in order for it to work, he had to be asleep. _Six hours for effect_, he thought before drifting off, _only six._

_**Let the fun begin**__._


	3. Morning

_It had been surprisingly easy to obtain the liquid he needed. Granted, there were a lot men keeping guard around the military base and passwords to decipher, but for Sherlock, it was easier than he had expected, perhaps __**too**__ easy. He was either becoming quicker at his deductions, or there were more simple-minded blokes in higher positions than he'd considered. Most likely the second option, but he did not doubt his intellect either. Sherlock shook his head and thought no more of it until evening fell and he was home._

_An hour later, a phone rang fifty miles away from Baker Street. Mycroft picked it up, listened for a moment, and then hung it up. He leaned back into his plush chair in the office and smiled. __**How predictable**__, he mused and without another thought, he sat up and went back to his paper works._

The alarm went off obnoxiously, a repetitive siren that screamed its purpose over and over again as it demanded to be heard. John's eyes snapped wide open and he reached over to fumble with the clock. _Where the hell is the snooze button?! _he thought frantically and at his wit's end, he threw the clock across the room, which miraculously, nailed the snooze button and shut it up once more. John fell back into bed and stared at the ceiling for a moment, exhausted as the adrenaline wore off. _Did I set the alarm on last night?_ he thought hazily and pushed it to the back of his brain. The room was quite dark and he could see sunlight trying to creep in through the blinds. This should have been the first sign that something wasn't right, but John was to distracted to think about it.

Finally, he yawned, sat up, and stretched. It wasn't until he stood up that he realized that something was odd. _I am feeling a lot taller this morning, _John thought and chuckled to himself, surprised by the deep, rough noise he produced. _Must have caught something..._ He looked down at his hands and his breath was caught in his throat. He stared at the long, slim fingers and flipped his hands back, so that his palms were faced upwards. They were pale, as pale as John had only been when he was a baby, but they were familiar as well. He looked around and confirmed his suspicions. John then stood up and ran to the bathroom. He looked into the mirror and his mind went blank for a mere second, but it was enough. John closed his eyes, took a deep breath, and yell with such volume that could shut an army of soldiers up, or in this case, wake the entire neighborhood up.

"**SHERLOCK!"**

* * *

Sherlock, on the other hand, knew what had happened the moment he opened his eyes. The light poured through the window and onto his (_John's_) face as he deduced that it was 9:15am on the dot. _But then again, was it 9:30am?_ he thought suddenly, unsure about his deduction skills for the first time in a long while. _Ah, it's part of the side effect_.

Sherlock swiftly sat up, heart pounding with excitement, and absorbed the information he observed at the sight of, well, everything. The way the bed was surprisingly tidy for someone who'd slept in it, the cleanliness (_blandness_) of the small, beige cubicle, the stubbiness of his calloused fingers, and sure enough as he strode to the wooden desk and opened the top right drawer, the well-armed and illegal gun. Sherlock rolled his eyes and knew that in a few minutes, John would be awake and aware of what had happened to him. He sat on the bed and glanced downward at his blue stripped pajamas, unsure whether he liked it or not, and slightly tempted to see the build beneath the thin fabric. _Later_, he decided.

Exactly 2 minute and 45 seconds passed by_._ Then came the sound he'd been waiting for. Sherlock got up and walked downstairs, closing the bedroom door silently.


	4. Confrontation

Sherlock strolled into the kitchen to prepare a cup of tea for himself and the quite angry man who was about to stomp down the stairs any minute now. He didn't have to wait for long.

"Sherlock Holmes, you put that kettle down immediately and turn around," John said as calmly as he could, but he was obviously seething in rage, each word almost came out as a spat. It was a bizarre feeling for Sherlock to hear himself saying this in his own deep, gravelly voice and as he turned to face John, the first thing that popped out of his mouth was, "Is this how it feels to be short?"

He hadn't meant to insult John directly, but the height difference was quite striking and unnerving for Sherlock, who had almost always been the one to look down at others, both physically and mentally. He noted his curly, dark-brown hair, lean figure, fair skin, and every other feature of himself that he was familiar with. It was interesting looking at himself from a different perspective and from John's impression, he could tell that he thought he was quite a looker. His smirked unashamedly as he walked closer to his original body and took a look at the one side of his figure that he himself rarely checked out.

John was rendered speechless at both the unexpected question he was asked and the sight of himself saying it. It was very disconcerting, not only to see himself in the eyes of another, but to see Sherlock's expression on his features. His face was stripped of all emotions, beside the obvious hunger for knowledge, the slightly mad look Sherlock had whenever he had a particularly interesting case, and an unusual smirk that basically screamed "I know, I'm hot." Above all John also accepted, quite grudgingly, how striking their height difference were. He was basically towering over himself. He stared guardedly, arms crossed, at Sherlock as the consulting detective, and officially the mad scientist, walked closer to him and did a full-body checkup.

As Sherlock checked out the back portion of his body, he looked down and called out smugly, "Ah, now I see why you're always checking out my arse," and before he was finished with his round, he gave John a slap that startled the doctor into finally being able to piece his thoughts together.

"Hey, watch it!" John glared, cheek slightly tinted red. He hadn't meant to stare at Sherlock's butt the time he'd known him, but every now and then, his eyes would somehow drift there and stayed for a moment or two before looking elsewhere. "I have killed many men before, so you better give me a good reason why I shouldn't add you to the list.

"Well, for starters, you need me to explain why we are the way we are, and how to reverse it," said Sherlock as he walked his way to the sofa. "Secondly, you probably want to know why I did this and what for."

"Actually, I don't really think I do," John retorted and sat in the armchair with a huff. "All I'm asking is for you to switch us back. That's all, And then you can head back doing what you usually do, experimenting WITHOUT me."

"Ah, but that's no fun," Sherlock complained, "Get change and meet me back here in ten minutes."

John glared at him, picturing a hundred ways to kill him, each one worse than the previous.

"Fine, you can kill me later. Just hurry up. Ten minutes," Sherlock called out as went to his (_John's_) room. The door shut and the blogger was alone.

"The nerve of that man," he muttered, feeling even more annoyed at the sound of the detective's voice coming out of his mouth. He scratched his head and finally, went upstairs into the bathroom.


	5. 10 Minutes

**A/N:** This is a mini scene (scratch that, it became a lot longer than I'd anticipated by the time I was done with it) about Sherlock and John's experiences with seeing their bodies bare in the bathroom for the first time. I believe that this fic is also going to be longer than 5, 000 words. I'm sorry if you were expecting for a brief story. It was originally supposed to be short and funny, but I suddenly had SO many ideas. This is most likely going to be less than 10, 000 words, but judging by my approximation, who knows? Anyways, thanks for sticking with the story up to this point and I thoroughly enjoyed reading your reviews!

**Warning: **Mild nudity and suggestive thoughts.

* * *

Sherlock stood in the bathroom and stared at his (_John's_) face in the mirror. He was slightly hesitant to undress and shower, not because he thought that it was an invasion of privacy, but because he wasn't quite sure what he would see there. He had thought about closing his eyes and not looking down at his body, but that was just ridiculous. Besides, he was also curious and he knew that once he was interested in something, nothing could change his mind. Curiosity could indeed kill the cat, but that was how Sherlock lived life.

He slowly unbutton his pajamas top and dropped it to the ground. John had quite a nice chest, smooth and firm, with slight blonde chest hairs that were barely visible upon his fair skin, although not as fair as Sherlock's. He wasn't as tan as he was a month ago either. _Broad shoulders, tight abdominal muscles_, he observed, _and... the bullet wound on his right shoulder_.

Sherlock had always known that John was shot and therefore brought back to England from the war the moment he laid eyes on him, but the sight of it still surprised him. It was a slight scar now, pink within and around the diameter of the puckered skin where the bullet entered his body and was later removed. _The kiss mark of a near death experience_. He gingerly touched the scar and was shocked by a memory that came almost instantaneously.

_Pain. So much pain. Am I going to die? It's okay. No one will miss me too much, besides Harry, but she probably won't noticed anything in her state. How could I let myself get shot so easily? Stupid. Idiot. God, I suck at saying goodbye, even in my mind._

Sherlock gasped and the memory disappeared as quickly as it came, but he could still feel the humid heat of the war and smell the metallic scent of blood.

"That was more vivid than it said it would be," murmured Sherlock, sweat forming above his brows, and he dropped his hand from the wound, careful to not touch the small area again, "Now, the bottoms."

* * *

John had been staring at his reflection for a good five minutes, not sure where to start. Should he shower? But that required taking off his garments. Should he brush his teeth instead? Maybe, but he'll still have to shower eventually and the mere thought of seeing Sherlock's nude body sent blood rushing to his face...and maybe even other parts of his body. He was definitely more bashful than the detective, but after convincing himself that this was all Sherlock's fault and he didn't care if Sherlock didn't want him seeing his bare body, John took off his shirt and threw it into the hamper.

He had been meaning to avoid any sight of his body, but an accidental glance took hold of his gaze and John could not turn away from the mirror. Sherlock's upper body was quite different from his own. He was genuinely surprised by the sharp cuts of his shoulder blades, the long, narrow waist, and the solid torso. _Impossible_, the doctor thought, _how could he be this fit if __he barely even moved when he didn't have too!_

Sighing, he began to pull his pajamas bottom down, but his hands refused to budge. _Come on_, he frowned, _it's just like examining a patient's body. Nothing to worry about. _His hands were stubborn, so John groaned and gave up. He slumped to the ground and placed his hands on his face. He couldn't understand why it was so hard to remove his clothing and get into the shower. As a former army doctor, he had examined many of his comrades' bodies for injuries, including his friends, without much thought, nor hesitation. He had never felt any form of emotions regarding that either, until now. It wasn't like Sherlock was bad-looking. Quite the contrary actually, but John would never admit that. Perhaps he felt this sort of closeness with Sherlock that he had never felt with anyone else, including past girlfriends, which made it so awkward to see his body disrobed.

_Okay, let's get this over with_, John stood out, eyes determined, and undressed himself before another thought until he was completely nude.


	6. The Blank Canvas

**Warning: **Mild nudity and suggestive thoughts.

* * *

_The two men were lost in the the smooth curves and cutting edges of their bodies. It was breathtaking in a sensuous way, like an artist would see a blank canvas and imagine all the ways it could be painted, like a writer would turn a new page and imagine all the words that could be written. The lines, angles, shapes, forms, textures... It was overwhelming. Eyes gazed downwards, from the pelvis girdle to the groin to the kneecaps to the feet, and everything in between. They wanted to stay there in solitude, to examine every square inch of the largest organ on the human body. But besides beauty, their overloaded senses triggered a particular chemical in their body, the one that ignited... lust. Whether they denied it or not, it was a fact that they were aroused by the appearance of their counterpart's body. As strange as the turnout of this event was, there was no doubt that they quite enjoyed the guise of one another, much more than they believed they should._

The duo showered, changed into their attires, and headed downstairs. Sherlock was the first to get there and waited patiently as John appeared in the living area of 221B. Neither spoke of their experiences, nor did Sherlock try to deduce why John took a 'longer than usual' time to shower. Without communicating, they came to a mutual understanding that some things should be left in private.

Twenty minutes had passed since they last spoke, but neither of them noticed.


	7. Rules

"There are many dark secrets in which you and I hold, and I will respect yours if you will mine," Sherlock said in a serious tone, "If you feel the mind resisting as you try to recall my memories, that's a sign to stop 'remembering' and think of something else. Got that?"

"Yes, yes, I got it," John rolled his eyes and finally accepted the cuppa that Sherlock had made him. He still did not trust that it was safe to drink it, but what more could go wrong? _I'm already stuck in my freaking flatmate's body_, he thought exhaustedly, _this is definitely not going on the blog_.

Sherlock stared at John drinking his tea in the armchair across from him. His choice of outfit would appear to be the usual to an average (_amateur_) person, but Sherlock's keen eye noticed the small corner of a light brown button-up shirt beneath his peacoat, a shirt that had been tucked away and stuffed at the bottom of his drawer, forgotten and untouched. He deduced that the change had unsettled John more than he was displaying and he needed something, anything, familiar to hold on to. Sherlock grimaced in distaste for the choice of color, but said nothing. It was understandable.

"So how long will this last?" John finally said after he took a sip.

"Twenty-four hours," Sherlock replied, "We both took it at approximately 8:30 pm last night and it takes six hours for our consciousness to switch, so by tomorrow morning, you will find yourself as John H. Watson once more, physically of course."

"One day," John breathed. _Okay, it's just one day. Not likely that he could get into any bloody trouble in my body by then._

"Yes, twenty-four hours is one day. Good job," Sherlock spoke sarcastically and before John could react, he said, "Now, listen closely. Soon, you'll be experiencing emotions toward certain places and people that I normally do and vice versa. Your mentality will also become like mine, or close to mine anyways. We are just mere observers, living within each other for the time being and witnessing life from a different point of view. Memories may surface every now and then and with enough control, you can make the body act like your usual self, but that will raise suspicions. I reckon we keep this a secret for obvious reasons. Do you understand what I am saying?"

"Of course. I may not be a genius like you, but I am certainly not a thick-headed bloke."

"Good. I rather not have someone walking around in my body spewing nonsensical utterances and making half-witted remarks." Sherlock turned and lay on the couch, eyes closed and palms together slightly above his chest with his fingertips touching his chin. John still could not get used to how unusual this experience was, especially seeing his own body in Sherlock's 'thinking' position. He sighed, leaned back, and stared at Sherlock's (_his_) head, testing to see if looks can actually kill, or at least, burn holes.

"Yes?" John heard a voice coming from his former body.

"You know, I could still kill you," John glared, "I need a better reason why I shouldn't go upstairs, grab my gun, and use you as a target. After all, this body had probably little experience shooting and I could use the practice."

"Surely you can't be that slow?" Sherlock said, surprised, as he twisted his head and glanced up and down his original body, "I assumed you've caught on by now."

The realization dawned on John as he tried to recover from his blunder, "Well, there's always tomorrow when we're back to ourselves."

"Ah, yes, but I'm betting that this is something you can benefit from," Sherlock turned his head back and gave a slight smile, but from his position, John would not have noticed it.

"Enlightened me."

"Well, haven't you ever wanted to look at the world through my mind and see what I see?" Sherlock stated, eyes closed again, "Of course you do, judging from the number of times you say 'fantastic' and 'amazing' whenever I deduced something. Actually, it's just plain obvious, but I can give you a list of observations if you like."

"Sherlock."

"Yes?"

"Just shut up."


	8. Ravenous

**12:00PM**

John stood in the kitchen making lunch while Sherlock laid on the couch in the same position that he'd been in about two hours ago. In fact, he hadn't moved since and as John was about to conclude that the detective had fallen asleep, there was a knock on the door and Sherlock's eyes opened. He groaned and turned his body towards the inside of the couch, refusing to acknowledge the sound, so John sighed, rested the can opener on the worktop, and walked towards the door. He placed his hand on the doorknob and a deduction formed out of the blue. _The knocking_, he realized as his mind begin reeling, _the intervals, loudness, and duration, it's Mrs. Hudson!_

John turned warily at Sherlock and wondered if he knew how his knock sounded like as well.

Wait... yes he does, along with his footsteps, typing, finger taps, etc. John shook his head. He didn't want to find out what else Sherlock knew about him. It would be too...weird.

"Good afternoon, Jo..." she started as he opened the door, but stopped with surprise, "Oh, hello Sherlock, I thought you were John." She chuckled, "He usually answers the door when I knock."

"Yeah, well, I think he's 'busy' at the moment. Come in."

Mrs. Hudson daintily walked in, her small and fragile frame hiding a feisty, headstrong woman, and as she turned towards Sherlock, her eyes widen and she began to look worried.

"John, dear, are you all right? You seem a bit...tired."

"Fine," came a muffled voice, his face pressed into the cushion, "I'm just...ravenous!" Sherlock quickly turned and sat up, startling both Mrs. Hudson and John, "I'm quite famished. When was the last time I ate?"

"Um, last night, I supposed," said John as he stared at Sherlock's confused face.

"Last night? Impossible. How can I be this hungry when I ate just recently?! No, I must have gone without food for at least three days by now."

"Three days... Oh," John's eyes lit with understanding as he stared into the kitchen. _You're not used to eating on a regular basis, so my high metabolism is something new to you._

"Well, let's eat then!" he said as he turned at Mrs. Hudson and smiled, "Care to join us?"

"No, d-don't work about me, dear. I'd already eaten lunch," she said, slightly dazed by John's offer, "I just came up to check on you two." She gave one last motherly smile and left the room, leaving John and Sherlock alone again.

John went back to the kitchen, finished making a couple of tuna sandwiches, and sat in the armchair, reaching out his hand with the plate towards Sherlock.

"Eat," he ordered and watched as Sherlock stared at the food for a moment before taking a piece. John leaned back and looked at the remainder on the plate, not feeling hungry, but knew he should eat. After all, this might be one of the rare moments to force food down Sherlock's throat. So he did.

* * *

**3:00PM**

Sherlock was up and about now, looking around the living room with 'new eyes' and observing how John saw the living area. _Unruly_ was the first description to pop into his mind, but _familiar_. John may appear to be a clean-cut, straightforward man, but on the inside, he was quite intricate. Sherlock felt John's ache for action, but at the same time, he felt his pain from lost lives and old scars. His days in the army had really affected his physical and emotional being, so although John craved deeply for love and affection, he was also subconsciously pushing potential lovers away in fear of losing or hurting them; hence, his many failed relationships.

Sherlock had never understood why John kept pursuing women who were most likely going to break up with him eventually or why they was important to him, but being stuck in this body, he was finally able to comprehend the longing for companionship and taking chances on love in a way that he had never felt. Why John never pushed Sherlock away was somewhat of a mystery that even his body didn't quite know. Perhaps they shared a special relationship that was neither platonic, nor romantic; a relationship that was just 'John and Sherlock' or 'Sherlock and John'... or John just didn't see Sherlock 'that way'. After all, he was quite defiant on being thought of as gay and the fact that many people saw the duo as a romantic couple. _It's not like that, _his mind and mouth kept repeating, but sometimes, Sherlock realized, John himself wasn't quite convinced by the affirmation.

Sherlock passed by his old friend, the skull that sat on the mantelpiece, as he made his way around the room and felt comforted by its presence; apparently, John had grown pretty fond of it as well over time and even chatted about trivial topics with it when Sherlock was either away or busying himself with experiments.

He decided to check out the kitchen and opened the fridge to study the new jar of fingers he had put in a couple of days ago. His body immediately recoiled and hand closed the door before Sherlock's mind was able to process what had happened. Ah, he forgot to mention them to John, so he didn't know about this side experiment. However, what surprised Sherlock was that John's mind and body were startled by the body parts in the fridge, but not completely upset by it. Yes, it was 'disturbing' and had apparently interfered with putting in things that were meant to be in fridges, like food, but John was not as against these experiments as he vocalized and complained to Sherlock. _How interesting..._

* * *

John, on the other hand, had dove deep into the novel he was reading when Sherlock's phone started ringing on the coffee table. Before he could reach for it, Sherlock swiftly walked over and answered the phone.

"Lestrade, what do you need?" Sherlock demanded.

"John? Why are you on Sherlock's phone? Is something wrong?" Lestrade asked and Sherlock mentally kicked himself.

"Oh, no, he's fine. I just happened to be closer to the phone... I'll hand it to him," Sherlock reluctantly gave his phone to the bewildered blogger who managed to get his composure in time. _Just go with it_, he reminded himself before answering.

"What do you need, Lestrade?" John asked, ignoring his own feeling of apologizing for sounding rude and letting the body's instinct take over.

"I need you to return those files you swiped last week," replied Lestrade, sounding tired, "Don't play dumb with me. I know you took them and by now, you should have gotten the information you needed."

"And by now, you should have gotten your personal affairs sorted out. No, don't answer that. I will be down at Scotland Yard in fifteen minutes," John hung up before the inspector could said another word and felt horrified by the way he'd responded. God, no wonder so many people hated Sherlock. How in the world did he tolerated him?

John walked over to Sherlock's working space and pulled out the files. Sherlock had been surprisingly quiet after the conversation with Lestrade, but he managed to get into the black cab with John and soon, they were standing outside the tall headquarters of Scotland Yard.


	9. Scotland Yard

**3:30PM**

"Freak alert, everybody," Sally Donovan called out from her desk as she saw John and Sherlock walking towards Lestrade's office. With an immense amount of effort, John bit back the insult on the tip of his tongue, turned to her, and gave her a tight smile.

"Good day to you too, Donovan," John said and internally chuckled at her wide eyes and gaping mouth as he continued walking. He turned to the other man watching him and said, "You too, Anderson." Anderson's brows furrowed with confusion and suspicion as he quickly stole a glance at Donovan and turned back to his work, slightly pinker now as he wondered what could Sherlock have meant by that.

_Donovan and Anderson are certainly getting more creative with their actions, especially last night, _John thought, suppressing another sniggering laughter, _look at the sight of those hands, her obvious attempt to straighten that matted hair, the way she's sitting, the sound of her voice... my god, it's a wonder they hadn't been arrested for public disturbance. _John could almost feel Sherlock silently trying to hold back his laughter as well beside him when they finally reached Lestrade's office.

Sherlock felt odd being the recessive one out of the two; he had been letting John do much of the talking and was even a step or two behind John as they waltzed into the cubicle without much of a notice.

Lestrade didn't even have to look up to see who it was and merely raised a hand for the files. John dropped them into his opened palm and begin to stride out when Lestrade called out, "Oh by the way, John, Ms. Sarah Sawyer have been trying to reach you. Apparently, you haven't contacted her in a few days and she's worried enough to stop by and ask me. Did you two have a little domestic?" He finally looked up from his paper works and stared at Sherlock with concerned eyes.

John was surprised when a sharp pang of jealousy suddenly struck his (_Sherlock's_) core hard enough to make him stumble a little. Apparently the name of his current girlfriend had sent quite some negative emotions into Sherlock's mind and body. Several thoughts ran by and John could do all, but listen helplessly to them.

_Why does John spent so much time with her? Am I too dull? Is he bored? What does she have that I don't? She just a mere woman who can only satisfy him through physical means. Ah, maybe that's it. Maybe I could..._

Meanwhile, Sherlock was so startled with the question that his mind went completely blank.

"Uh..." was the only somewhat coherent word Sherlock could produce before continuing, "No, not at all. I've just been quite busy working on a project with _Sherlock_ and have sort of misplaced my phone."

Lestrade frowned and said, "Okay, well, if you need anything... just let me know."

"Yeah, sure," Sherlock mumbled and walked quickly out of the office. John had collected his thoughts by now and followed him out, giving Lestrade a quick nod, leaving the man feeling a bit bewildered and that something was different, but he could not pinpoint the source.

As the duo rode silently in the taxi cab, John debated on whether to confront Sherlock regarding his hostile feelings towards Sarah, but he couldn't find the courage to do so. After all, this was Sherlock's private thoughts and to talk to him about it seemed to cross an unspoken line. No, he was not going to open that discussion with him and that was set.

The cab arrived on Baker Street and by now, it was time for supper.

* * *

**8:00PM**

John had finally finished the book he was reading. It was a pretty decent crime fiction and had somewhat reminded him of his life with Sherlock. How funny is it when life becomes similar to a novel. Sherlock had already went to his room for the night, but was unclear whether or not he was still awake.

John leaned back, stretched like a cat, and accidentally stubbed a foot on the leg of the coffee table. He winced slightly at the pain and scowled himself for forgetting that since he was in a much taller body, he was able to cover more distance than before. _I supposed if there's one thing I'll miss, it would be being able to reach higher places and tower over Sherlock for once. _He chuckled to himself.

One thing, out of many, that he would not miss, though, was that although Sherlock had a very competent mind, it would simply not stop racing. Everywhere John looked, there was a story behind it. The carpets, for example, were about five years old, having been stepped on only a few times before he and Sherlock rented the place, judging by the flattened fibers, which indicated that not many people had lived here previously.

It was worse when John stepped outside the apartment to take a walk or buy some groceries, although he once tried to make Sherlock buy milk instead because of their state, but Sherlock was ever so resistant. Whenever John glanced at a person or chatted with an acquaintance, he would immediately deduced their life story, which sometimes made conversations awkward when he found out something that he shouldn't have and biting off the temptation of letting them know that he knew. _Maybe that's why Sherlock rarely keeps people close to him, _he deduced, _his mind was both a blessing and a curse._

It was with great effort that he remained calm and quiet instead of bouncing around the room with this bottled-up energy that needed to be release because he had nothing to do. John resorted to tapping his fingers mindlessly on the armrest of his chair. His mind was already in full speed calculating the displaced volume of blood a five foot six victim weighing nine stones would have loss should he be stabbed in the forearm with a penknife, therefore severing an ulnar artery and slowly bleeding for half an hour to death. He found out the answer in half a minute.


	10. Memory (Part 1)

John decided to push the mind a little further and find out more about Sherlock, for this might be the only time to do so. He picked his book up and went to Sherlock's bedroom, setting it down on the nightstand before turning off the light. He laid on the soft bed and closed his eyes, finally letting down some, _only some_, barriers the 'Mind Palace' had built. The memories came pouring out like a waterfall and John gasped as he became submerged into it.

* * *

_It was a warm sunny day, blindingly bright with a moderately steady breeze. There was rustling sound of leaves as the wind gusted through its branches, wrapping them in its cool touches, then finally settling down only to start up once more. The sky was as blue as the grass was green on the well-trimmed lawn just outside the Holmes estate. Five-year-old Sherlock was running forward, panting lightly with his dark curls bouncing on the crown of his head. He was meeting someone, someone special to him. The sun was in his squinted eyes, but as he got closer, a figure eclipsed the bright light and Sherlock stopped, panting heavily now. He widen his bluish-green eyes, broke into a wide smile once he found who he was looking for, and ran to hug his twelve-year-old brother, back for vacation from his boarding school. Mycroft looked at the boy fondly and patted his head. He took Sherlock's right hand into his left and they walked to the mansion together._

The memory faded out and in came another one.

_It was an evening in mid-July. Sherlock was eleven now and sitting on an armchair too big for his small frame. It was his father's chair, but Mr. Holmes had been gone for three months as of yesterday, investigating a breach in the British embassy of Spain. Mummy Holmes was upstairs calling all sorts of people, from local police chiefs to army generals, and was too busy to look after Sherlock most of the time, but there was no need do so, for since the age of nine, he was already quite capable at taking care of himself._

_Sherlock was reading a crime fiction novel (oh, how fascinated he was by the mysteries and puzzles, even though he had already solved them before he was halfway through the book ) when he heard loud footsteps getting closer to the front door. Immediately, he slammed the book shut and ran toward it, eager to greet his brother. What Sherlock did not expect was Mycroft storming into the house angrily and shoving his brother roughly aside to go upstairs and have a word or two with Mummy. Sherlock was too numb with shock to feel pain as he sat against the wall perpendicular to the door and listened to the loud arguments in the room upstairs. After a few minutes, the house became eerily quiet. Then Mycroft strode downstairs, two steps at a time, with a suitcase and went out the door the same way he came in, but this time, he did not see his little brother sitting there; it was as if he didn't exist at all. That was the last time Sherlock ever saw his brother in his childhood memories._


	11. Memory (Part 2)

The memory faded out yet again and in came the next; this one was more reluctant.

_A pit of darkness. Well, more of a shallow ditch, but close enough. Everything was so...dark. So alone. He was so alone in the dark. Cold, yet strangely warm. Ah, the blood, yes, how many times was he struck? Five, six times? Maybe, he'd lost count. It has been pouring in London since 6pm (it should be about nine by now), but Sherlock had been laying there for only half an hour. It almost felt...comfortable. The cool, slight trickle of rainwater flowing around and against his feverish body. He could stay here forever, just drift off to a peaceful sleep. And so he did._

_Sherlock was still half asleep when his mind became conscious again, but he could faintly hear two distinct voices of a woman and a man._

"_So how did you find him again?" said the woman. There was a scribbling sound coming from her direction; she must have been a police officer or a nurse. Probably the latter._

"_I got a call from an anonymous witness saying he saw four college guys beating up a bloke and dragging him away. When I got there, there was no one in sight, so I walked around and found him laying in the ditch, all battered up and unconscious." the man replied._

"_Do you know anything about him?"_

"_No."_

"_Thank you for your time, Sergeant Lestrade."_

_The room was bright, too bright. Sherlock was blinded the illumination, even with his eyes close. This place, it felt so sharp, so sterilized, much like a...hospital! He sat up, eyes finally wide opened, and felt a sharp pain in his head. Sherlock grimaced and looked around. He was not hooked up to an intravenous catheter (thank god), so he must not have loss too much blood or broken any bones, but every part of his body was aching as if he had run a marathon without warming up. What happened? Sherlock was in a ditch, yes, but before...ah. He had been cornered in the university hallway by several thick-headed blighters who were drunk and looking for a fight. Two of the blokes were his classmates and Sherlock had very bad experiences with them before, due to his "sociopathic" behaviors. Being slower-minded and less coordinated due to their intoxication, Sherlock managed to outwit them and run away, but they soon caught up to him and starting beating him up. Although Sherlock was not weak back then, it was him against four large football jocks, so the odds were not looking good for him. Realizing that there was no way out, Sherlock gave one last witty insult that sent him right into the ditch. The rest was history._

"_Take it easy, chap, you've taken quite a hard hit, several actually," Lestrade came over when he saw Sherlock sat up._

"_Really now?" Sherlock replied, voice dripping in sarcasm. He didn't care if he had offended the sergeant. All he wanted was to get out of this hospital (St Bartholomew's Hospital, he presumed) and go back to his dorm. "How long do I have to stay here?"_

"_About three days." Surprisingly, the sergeant did not look upset by his previous remark. "Better make yourself comfortable."_

"_I can't stay here! It's too long," Sherlock protested and started to get up, but not before Lestrade took hold of him and forced him back._

"_Now where do you think you're going?" he said, "especially while you're still dressed in that."_

_Sherlock stopped and looked down at his garments, which were replaced by a hospital gown that was loosely tied at the back. "I'll just walk back to the university."_

_They stared at each other for a moment before Lestrade finally believed that he really would. He sighed, left the room, and came back with a pair of trousers and shoes, a shirt, and a jacket._

"_I'm not supposed to do this and I don't even know why I am, but take these and go before the nurse come back for another check-up. I'll cover for you," Lestrade said as he threw the garments to Sherlock. He caught them with surprise and slight suspicion. No one has ever tried to help him with anything in a very long time._

"_Thanks," Sherlock replied cautiously as he changed and started heading towards the door._

"_By the way, do you perchance know who assaulted you?" Lestrade asked before he left._

"_Two of them are in my class: James Davies and Cole Stuarts. As for the other two, I don't know them, but I know that they're on the football team, have grades ranging between high D's and low C's, took a Chemistry class last year together, have known each other since high school, and one of them was born in Newport while the other in Manchester. Good day." And with that, he strolled off, leaving a gaping sergeant standing in the room. As he stood outside the hospital, Sherlock placed a hand in his pocket and pulled out a business card._

"_Sergeant Gregory Lestrade. Scotland Yard," he read and noticed the contact information at the bottom of the pearl white slip, "I might need this someday."_

_Sherlock reappeared in front of Detective Inspector Lestrade of Scotland Yard ten years later for the first time since their unexpected encounter._

* * *

Morning came and John realized that he had fallen asleep through the night entwined in dreams and memories of Sherlock's past. He had a newly found respect for the detective in a way that he never had before. The knowledge of what Sherlock went through was very emotional, but not surprising. Sherlock was not the sociopath he tried to convince everyone he was, including himself, and John had already knew that by the end of the Study in Pink case. These lost feelings were just buried deep inside Sherlock, or more appropriately, chained and locked up in the basement of the Mind Palace to prevent anything from hurting him and his work.

To feel love or pain or sadness was a sign of weakness to the detective. They were the uncontrollable factors of experiments, the sources of errors. Whatever Sherlock didn't like, he got rid of them or hid them from his sight. However, these emotions were no longer mere shadows, for John had seen their true forms and freed them, even for a moment, from their prison. And for that one instance in time, they burst and soared and rode through each vein down to the capillary of Sherlock's iron heart, melting the silver coating with icy heat and releasing them throughout his body, finally imploding into his very core.

Morning certainly came, but the body and mind of the great Sherlock Holmes were no longer the same.

When John woke up, he did not feel any different. Granted, he was not expecting to feel anything as he did the day he woke up as Sherlock, but he thought that perhaps a sense of familiarity would wash over him. The first thing John decided to look at were his hands, as he had the day before. He glanced down expectantly and stopped breathing.

_I am still...Sherlock._


	12. Operation Mind Switch

John was sitting in his chair, staring warily at Sherlock as he paced back and forth furiously.

_This is all wrong. What happened? We were supposed to be switched back about eight hours ago when we were asleep. Maybe something we did yesterday paused the time progression of the chemical that switched our consciousness. Or perhaps it's something different altogether. But what could that be?! What could..._

Sherlock stopped and listened. The door of the building opened and closed with a thud. Mrs. Hudson was away visiting Mrs. Turner, so the door should have been locked. A sound of leisure steps echoed softly through the flat as the intruder ascended.

_Oh... stupid, stupid, stupid._

"Good day to you, Dr. Watson... Sherlock," Mycroft purred as he sauntered in, swinging his umbrella round and around. He began to smirk at Sherlock.

"Fancy meeting you again, little brother. You seemed to have gotten a lot...shorter than before. Took you long enough to figure out. Maybe that body really is slowing down your thought process, no offense John." The blogger gave him a tight smile.

"Mycroft," Sherlock growled and walked towards his brother, looking quite dangerous even in a smaller frame, but his brother simply rolled his eyes, "What did you do?"

"Oh, let's just say I 'accidentally' mislabeled the container and that it does not take twenty-four hours to change back. In fact," he said coolly as he pulled out a small vial, "this is the solution that will reversed your current state, _the only one in the world_.

Sherlock's (_John's_) eyes narrowed as they locked with Mycroft's for a few seconds, sizing each other up mentally. Finally, Sherlock let out a defeated groan and plopped onto the couch with his arms crossed. It was childish, but that was all Sherlock could do after realizing that his brother had the upper hand in their situation.

"What do you want from me, Mycroft?" Sherlock grimaced as he uttered those words.

Mycroft grinned and pulled a folder out from his suit, and handed it to Sherlock. John, who had been sitting in his chair since Mycroft waltzed in, finally stood up and came over. There was only a sheet of paper in the folder, which contained nothing, but a name: **R. Brook**.

"So you want me to find this man for you," Sherlock deduced.

"My, you have gotten quite slow, haven't you? Oh, no, don't be silly. It's just a little murder case I would like you to solve, committed by this man, of course. I know how much you love murders. I'll call this," he motioned his hands and umbrella up into the air dramatically, " 'Operation Mind Switch.' Yes, it has a nice ring to it. This shouldn't take too long, at most a day. Once you're done, I'll hand the counteraction to you, no strings attached."

"Well, why the hell do you want me to solve such an...such an _elementary_ case that required you to, in a way, hold our lives hostage?!" Sherlock was fuming now, trying to weave his hands into his hair in frustration, but failing due to John's short cut.

"Why am I? Hmm," Mycroft pondered for a bit, fingers spread over his lips, then shrugged exaggeratedly, "Anyways, this is the information you'll need."

"What, you couldn't have stated them in this folder here?" Sherlock replied sulkily.

"Dull," Mycroft mocked, sounding eerily similar to his brother, "Besides, this case should be an interesting challenge for the _both_ of you." He regarded John's existence for the first time since greeting him. "Considering the fact that you, Sherlock, are lacking your deduction skills, and you, John, are not used to them yet. Such a disadvantage. _Tsk. Tsk._"

Before Sherlock could retort, Mycroft cut him off, "Now, for the case. We, the British government of course, have been investigating several major crimes that seemed to come down to one person, R. Brook. We do not know anything about him, not even his first name, but through multiple sources, this was what we came up with. He appeared to be the mastermind of the underworld in Great Britain, well, majority of it anyways, and we need to find him before he cause anymore trouble. However, all I need you and your _partner _to do is to find out what caused the death of Martha Gibbings, who was a senator in the UK Parliament, what was the motive, and any information you can get from the autopsy on Brook. Are we clear?"

"And are you still on that diet?" Sherlock asked innocently.

"Yes," Mycroft said with annoyance.

"Then so be my answer," he replied and the older man left the room without shutting the door.


	13. Dragon Well

**A/N:** Happy Thanksgiving! Gosh, this was the most difficult chapter to write for me. I am not familiar with much medical terms and symptoms and such, so to write this murder case had me in a knot for a while. Please be gentle on any mistakes I may have made in terms of the case. On another note, I am so blown away by the number of readers following the story and reviews. It may not be much to some, but that is a lot to me. On yet another note, judging by the number of words this fic now have, I give up. I really suck at guesstimating lengths and such. Thank you for your support and happy reading!

* * *

Sherlock and John arrived at the home of Senator Martha Gibbings an hour later. The place was peaceful and quiet, as if nothing had ever happened. It seemed that Mycroft had not had anybody working on this case before them either. Sherlock looked down at the cream-colored card in his hand that his brother had told him the murderer gave Gibbings a week earlier.

_**Dear Senator Martha Gibbings,**_

_I am such a big fan of yours. You are as pretty and fierce as a dragon well. _

_Please keep up the good work in the British Government. England needs it._

_Love,_

_**R.B.**_

As the duo entered the bedroom, they noticed the woman lying in a twisted position on the floor. Sherlock looked around intensely, but stopped short when he realized that he couldn't observe as much as usual. It felt odd, as if he had lost a limb or a sense. He groaned in frustration and stared at John, who in turn, threw him a brief sympathetic glance. Sherlock was startled when he saw the strange emotion crossing his former face; he had never made such an expression before...ever. As he stood in the room, John closed his eyes and inhaled. Then, he opened them and observed the woman.

She appeared to have dressed for a formal meeting, wearing a purple silk blouse, knee-high navy pencil skirt, black leggings, and sleek court shoes. On her face, she just wore mascara, rosy blush, and magenta-colored lipstick. Everything seemed normal, except for her body position and slightly blue, swollen face. Gibbings had appeared to be in a lot of pain, but as John bent down and tried to diagnose the cause of death, he found that he wasn't quite able too. Confused for a moment, he realized that if he had gained Sherlock's deduction skills, then Sherlock must have gotten his medical ones.

"I reckon you come over and help me, instead of standing idly," John called out. Sherlock, who was beginning to think that he was of no use without his observations, walked towards John uncertainly and bend down next to him.

"Diagnose her," John simply said. Glancing up at the doctor for a moment, Sherlock looked down at the body and let the body's instinct control him.

"She had suffered some kind of shock," he muttered, then pulled the eyelids up, "Subconjunctival hemorrhage in the eyes." He looked at her face, "And lack of oxygen, most likely due to swelling in the trachea, therefore dying of asphyxiation. But what could cause this? There are no signs of bruising on her neck, so she wasn't strangled."

John had been walking around the room, looking for clues that may lead to the diagnosis, when he opened a drawer and found a bottle of antihistamine pills.

"She had some sort of allergies," he came back with the bottle and handed it to Sherlock.

"Allergies..." the detective whispered, "Allergies... Allergies! Yes, that's it. She died from an anaphylactic shock." Sherlock's eyes were glowing with accomplishment.

"Fantastic," John grinned, looking impressed.

"I seemed to have underestimated your capabilities," Sherlock admitted, looking up at the doctor.

"And I'll take that as a compliment," John laughed and the detective smiled.

"Okay, so we know what the cause of death is, but how was she murdered? We know that Brook had gotten something Gibbings was allergic to into her system, but it had to be a catalyst that reacted instantaneously; there was no sign of intrusion, nor physical marks on her body that would've indicate that he injected some sort of reactant into her."

"Hmm," John pondered, "Give me that letter again." Sherlock walked over and handed it to him, their fingers brushing ever so slightly, but he could feel the little touch vividly.

"Let's see," John reread the lightly lemon-scented letter, "Dragon well... that's a really odd description. What could that mean?"

"Mind Palace!" Sherlock stated suddenly, startling his partner.

"What?" he replied, confused when the detective moved closer to him and put both hands on each side of his head. Because he was in John's body, he had to pull John's (_Sherlock's_) head downwards, closer to his face.

"The Mind Palace. You have to get inside it. My mind is like a hard drive; it stores countless information and if you can get into it, you'll find the answer. Now close your eyes and think," Sherlock pulled closer to the doctor, their foreheads now pressing.

John blinked and obliged. He closed his eyes and tentatively relieved his consciousness to let the brain take over.

_**Dragon Well**_

Almost immediately, his mind was filled with pictures, data, descriptions, and observations of items ranging from the history of dragon myths to the depth of an average well, but nothing seemed to fit. There were just too much information filling up his brain and it was beginning to overwhelm John.

"I don't know, Sherlock. The words doesn't make sense together, nor does it relate to the case. It's just too much," he said softly, voice filled with defenselessness.

"You just need something that clicks, the missing piece. Just clear your mind of anything that doesn't make sense and think," Sherlock urged, tightening his grip slightly.

"I can't," John almost whimpered, eyes still closed. There was so much going on in Sherlock's hard drive that his consciousness could barely keep up with. This was the first time John had actually experienced Sherlock's full intellect capacity. Before, the information just leaked out subconsciously. Even when John had fallen asleep in those dreams and memories, he was able to wake up from it. Now, it poured without stopping. Feeling helpless and unable to stand his painful voice any longer, Sherlock did the only thing he could think of.

He shut his eyes, pulled John forward, and kissed him soundly on the lips.


	14. Chinese or Italian?

It was an odd sensation, considering that they were still in each others' body, but with their eyes closed and lips touching, it was as if the doctor and the detective were in their own being for a moment. John was completely surprised, but didn't pull away, nor opened his eyes. His brain, of course, had stopped functioning and all he felt were the warm, soft curves fitting perfectly into his own. He responded by tilting his head and opening his mouth slightly. He felt Sherlock's warm breath on his tongue and tasted the last thing the detective had before they arrived at the senator's home: **tea**.

And that was the missing piece.

John inhaled sharply and pulled away. Sherlock, looking a bit dazed, recovered a few moments later and studied his face. He smiled, knowing that the doctor had found what he was looking for.

"Tea!" John exclaimed, still slightly flushed, "She was severely allergic to tea. That's what dragon well is. Or more specifically, a special kind of tea known as Longjing tea, well-known in China for its quality and tasteless seed oil. Tasteless! My god, that's how Brook was able to slip it into her system without her knowledge."

His eyes were shining with that particular excitement Sherlock was very familiar with, the feeling of fitting the missing piece into its slot. The detective took a brief second to consider his actions, but decided that on the spur of the moment, it was the right thing to do. Even so, if he were to go back a minute ago and decide with more time, he would have done exactly the same thing.

"Now the question is, how did he get tea into her system without her knowledge?" Sherlock said and John's brows furrowed. The doctor bit his lower lips subconsciously and all Sherlock could think was that he had kissed them just a few minutes ago. Although it would appear strange and even a bit disturbing to think that he had literally kissed himself, Sherlock didn't and couldn't see it that way. All he saw was John H. Watson: army doctor, soldier, and blogger; the man who followed and trusted him, no matter their situation, regardless of how he appeared on the outside. And from the doctor's point of view, he saw the same thing in Sherlock as well.

The duo had been in the senator's house for about four hours now. It was close to six in the evening and by this time, they were quite famished.

"I say we have supper first. Shall I order Chinese or Italian?" John said finally, taking his phone out. He frowned for a moment, feeling as if it was not something he should say at a place like this, but shrugged. _Ah well._

"Are you seriously going to have takeaway meals delivered here? At a crime scene?" Sherlock replied in disbelief. _God, I am really turning into John._

"What? It's not like she's going to mind the smell," the doctor said and stared at Sherlock's (_his_) disapproving face, "Not good?"

"Nope."

* * *

Ten minutes later, the door bell rang and John went downstairs to answer it. There were no police tapes, nor 'Keep Out' signs around the area, so to an outsider, the house appeared to be the same as it ever was. He came back with several boxes of fried rice, dumplings, pork buns, and vegetables. The two men ate in the dining room and discussed more about the case, with Sherlock eating most of the food and John eating barely any. After all, he was working on a case and food would only be a distraction to him. No, he had to think if he wanted to get back into his original body as soon as possible.

"Now we know that there were no physical damages done to this woman, so the only options left are the oil must have been ingested, sniffed, or put into her eyes as a form of liquid," John began and started deducing, "Of course, we can eliminate the last two because there were no traces of oil around Gibbings's nostrils and on her eyes, besides the ones the body produced. Furthermore, that would be absurd. She wouldn't be sniffing oil or using it to clear her eyes. No, it must have been swallowed."

Sherlock ate while he listened and looked around the room. There were many pictures of the senator in the dining area, most of them were taken quite recently. _Gibbings appeared to be similar in all of them_, Sherlock mindlessly thought,_ same rosy cheeks, same posture, same cool façade, same open-mouth smile, same... wait a moment._

He frowned, staring closely at the pictures, one by one. They were all similar, yes, but there was something different in comparison to the woman lying on the bedroom floor upstairs. A nagging feeling was pulsing at the back of his head, the one that told him the answer was staring right at his face, hidden in plain sight.

"Sherlock?" John said when he noticed the detective standing up and walking towards to a photo frame of Martha Gibbings posing with the ambassador of the British Embassy in Berlin. He watched as the man picked it up and stared at it for a while.

_Come on, think!_ Sherlock mentally yelled to his mind,_ John may not be that observant, but he is certainly not stupid; a lot brighter than many blokes out there, even professional ones. What is different from this picture and from the woman lying upstairs? The outfit, for one thing, but that's not important. Her makeup is the same, too... well, she is wearing a much cheaper lipstick in here. Just look at that texture, the shade..._

"The shade!" Sherlock exclaimed unwittingly, causing John to jump, "The shade of the lipstick is much lighter in this image and all of the other pictures than the one she is wearing now, meaning that the one she's wearing is new, or perhaps, bought for her as a gift. The tea seed oil is in the lipstick! Brook must have made and sent it to her along with the card a week ago, so that when she used it, she would ingest some lipstick containing the oil and died from a severe allergic reaction without even being there. It's brilliant!"

Sherlock sat back into the chair with a satisfying grin, finally feeling more like himself again.

"That was amazing, I must say," John admitted after finding his voice again.

"Of course, as always," Sherlock smirked, "We should bring it to the lab and have it tested right now."

"Sounds like a plan." The two cleaned up their mess and left the house with the lipstick and card towards the laboratory of St Bart's Hospital. A little security camera followed them on the way out and Mycroft leaned back, observed, and smiled.


	15. HI

"Oh, Sherlock! Fancy meeting you here at a time like this," Molly said, looking surprised and slightly reddened as the detective and his partner entered the lab.

"A case cannot wait and you know that," Sherlock said, not bothering to look at her as he went to set up an area for the testing.

"Oh, and you too, uh, James," she said, confused when she saw 'John' answering back.

"John," the doctor corrected, confusing Molly even more when she saw 'Sherlock' replying.

_Damn_, the two men thought simultaneously. Sherlock stepped back and met John's eyes. They nodded slightly and John took over Sherlock's role in the lab while Sherlock took over his.

"So what are you doing here so late, Molly?" Sherlock asked, trying to cover the strange exchange they had and subduing a cringe at the question. He was not used to making these small conversations; it was always time-consuming and tedious.

"Oh, well, I had nothing better to do, so I decided a little more work would clear the good old noggin," she laughed nervously and an awkward silence followed. Clearly neither of them were good at making conversations. Giving up, he gave a half-smile and walked over to John, who had set up their station, but looked quite confused as to what he was supposed to do. Sighing quietly, he turned towards the doctor with his back to Molly and leaned close.

"I suggest the first thing you do is put your safety goggles on," Sherlock murmured into his ear, making John shiver slightly as his deep, gravelly voice vibrated through him, down to the base of his spine.

"Ah, right," John said and fumbled with the goggles, causing the detective to sigh again, reach for them, put the goggles swiftly over the doctor's (_clearly not a chemist_) eyes, and adjusted them.

"Thanks," John muttered, looking away with embarrassment. Sherlock smirked and began ordering him, under his breath, to melt the lipstick and heat it up until the liquid evaporate into the filter paper covering the flask.

Meanwhile, Molly had went back to her experiment, but haven't taken her eyes off either of the men since they both stepped into the room. _Something seems different_, she mused, pursing her lips as she thought, _it's as if they are not themselves, as if..._ Her eyes widen at the possibility, but she quickly dismissed it. _Nah, it can't be. That's impossible. But then again, this is Sherlock we're talking about..._

"Let it sit for about half an hour. It takes a while for the oil and wax to separate," Sherlock said and took a step back at last. He had been standing really close to the doctor, enough to feel their body heat radiating together.

The detective took out the card, looked at it for a bit, and left the piece of paper, which was of no use to him anymore, by the experiment. After John took out his goggles, the two leaned against a nearby counter, keeping an eye on the flask, and relaxed slightly. It had been a long day. Evidently, the day was going to get longer when they saw Molly walking over.

"So, how's your experiment coming along?" Molly asked, looking at the two of them equally and planning out her own little experiment.

"Fine," John replied politely while Sherlock was still lost in thought.

"Good, good," she responded distractedly. An aura of awkwardness filled the area soon after again.

_Okay, just do it and get over with it. The worst thing that could happen is if he reply the same thing as before and I can finally be at peace with this silly thought_, she mentally gave herself a pep talk. Molly took a deep breath, looked mainly at John this time, and said, "Oh by the way, Sherlock, I was wondering if you would like to have, to have coffee?"

"Oh, not now, thank you," John replied, feeling uncomfortable. He knew that Molly was deeply infatuated with Sherlock (_it was just plain obvious, but that man can be so bloody oblivious sometimes_), but he did not want her to get any ideas either. "I have to accompany _John_ with the... experiment, so I can't leave tonight. Sorry." One look at Molly's expression and he knew that that was the wrong response.

"You're not really Sherlock, are you?" she spoke softly, "John?"

The detective immediately snapped his head sharply towards her and stared piercingly as she watched the doctor. John was too lost for words and looked at Sherlock, waiting for him to respond to the question.

"How did you come to that conclusion?" Sherlock asked guardedly.

"I just...observed," she turned towards him, fighting the urge to shrink back and apologize. After all, what would she apologize for? Being right? Or was she even right at all?

They stared at each other for a moment. Any other time, Molly would have melted at the thought of having this much attention from Sherlock, but considering that he was in John's body (_possibly_), that did not happened. Finally, Sherlock sighed defeatedly and looked away. He had certainly underestimated the woman whom he disregarded many times in the past.

"Oh my god," she whispered with a hand lightly covering her mouth, "I was right."

"Please refrain from telling anyone of our state," John said and she turned back to him, still in disbelief, "It's just another of Sherlock's experiments." She nodded her head absently and took a few steps toward a parallel counter, resting her back against it and staring at them with new eyes now.

"How long are you going to be in this...state?" Molly finally asked after collecting her thoughts and accepting that what she had suspected came true.

"At the latest, tonight," Sherlock said and stood straight up suddenly, "And judging by that flask, I'll say we are going to be back to normal pretty soon." He quickly walked over to the experiment and turned off the fire, not even bothering to put on a pair of safety goggles. John and Molly followed him behind silently as he carefully picked up the now soaked paper with a pair of tongs and set it down on a slide, which he then proceeded to placing it under a microscope.

"I need you to look at the compound and see if it fits with those of the tea seed oil's," Sherlock looked at John at last and motioned him forward to take over. Still a bit unsure whether he would recognize it or not, John stepped forward and looked through the eyepiece. Immediately, he got the answer.

"Yes, that is it," he said, looking at Sherlock with relief. If they had been wrong, John really didn't know what more they could do.

"Okay, so we have the cause of death and how it was done, all we need now is the motive," Sherlock muttered.

"One thing I don't understand, though, is why did Brook gave us those clues about the dragon well and the shade of lipstick. It's obvious that he meant to choose such a light shade of colour to let us know the significance of it," John said, "He doesn't strike me as a daft bloke. Quite the opposite, actually."

Molly had been standing quietly and listening to their conversation, not fully understanding the situation, but knew enough to know that this case was somehow tied to their switch. She looked down and noticed the little card. As Molly picked it up, her lips formed a thin line and she handed it to them.

"Perhaps he was testing you," she said quietly, "and wanted to leave a note."

Sherlock and John looked down at the paper she was holding and found that over the letters, a darken word that had not appeared before was scrawled in large print: **HI.**


	16. Battlefield

"Invisible ink. That's why the card smelt faintly like lemons. The word showed up when heated and it had been sitting next to the flask all this time," John deduced as he took the paper from Molly, "Maybe there's more on the back..."

He turned the card over, held it close to his mouth, and exhaled on it. Slowly, more words appeared.

_**Very good. I suppose you are looking for more than**_

_**just this on the back. Don't worry, we'll be**_

_**meeting soon. Until then, ciao!**_

_**Richard Brook**_

"Richard Brook," Sherlock murmured, "Well, we know his first name now."

"I doubt it's his real name though," John frowned, " It was too risky for him to put it there. No, he must have been really sure no one would be able to trace him, even with his full name. This man is a freaking genius and a bloody psychopath."

"So the motive of killing that woman was to leave a blasted message?" Sherlock uttered disgustedly. Normally, he would have been indifferent, regardless of the reasons why murderers killed innocent people, but feeling John's experience as a soldier fighting and risking his life to save others, he slowly realized that although solving murder cases were his source of entertainment and hobby, there was a very twisted side to it, too. He had always known that, but never quite understand it until now.

"Seems like it," the doctor sighed.

"Do you think that message was meant for us?" Sherlock asked.

"Hard to say," John looked at him, "but considering what we know about Brook so far, it could be possible. Anyway, that's not what we were asked to do, nor our area of inquiry, so I believe we are done here. Better head to Mycroft now." Sherlock reluctantly agreed and as they gathered their belongings, a voice echoed through the room.

"No need for that. I am already here," Mycroft hummed and strode in leisurely, spinning his umbrella round and around as he go. Why he carried that thing everywhere even when it's not raining was a mystery.

"Her Majesty has arrived," Sherlock jeered and John chuckled. The elder Holmes pretended not to hear his remark and walked over to the detective and the doctor.

"No need to recap your findings, I have heard and seen them all. _All of them,_" he smirked.

"Never mind that. We had a deal," Sherlock reached his right hand out, not giving Mycroft the satisfaction of looking like he had been caught doing something wrong because, well, he didn't. True to his words, the man placed the vial into his open palm.

"This should take an hour to work. You don't have to be asleep, but you might want to brace yourself when it happens. Symptoms may include slight disorientation, dizziness, confusion, et cetera, et cetera. You can take it alone or in a drink, but both of you need to take it, of course. Have a nice life and remember, I'm always watching." He left and Sherlock watched him, feeling a bit uneasy. There was something in his brother's voice that he could not comprehend. Sherlock shook his head and grinned at John.

"We shall go home," he affirmed and the doctor agreed. John bade Molly goodnight and they left the hospital. It was eight in the evening by the time they arrived at Baker St.

* * *

Pouring the liquid they had obtained in a couple of cuppas, Sherlock walked over to John and handed him his.

"This shall be the last time I'll ever accept a cup of anything from you, Mr. Holmes," John teased and took it. He finished it in less than a minute and sat in his armchair, releasing the tension from his body and feeling bloody exhausted by now. Sherlock drank his, took their cups to the kitchen, and set them in the sink. He then laid on the couch across from John, closed his eyes, and waited.

An hour went by and nothing happened.

"Maybe it's just slightly slow," John said doubtfully.

Another hour went by and still, nothing happened. Sherlock had been pacing back and forth silently, trying to think of what could have happened. There was a possibility his brother could have given them a placebo, but based on his experience, he knew that that was not the case. Perhaps... it just doesn't work on either of them at all. Letting out a frustrated groan, Sherlock sat back onto the couch and looked down.

"I'm sorry," he said softly, "for putting you into this situation."

John was startled when he heard the sound of defeat and desperation in the detective's voice. That was a bad sign. Sherlock never gave up on anything, unless it was too late. He stood up and walked over to sit next to him.

"Well, we all make mistakes, don't we?" he chuckled, but Sherlock did not reply, nor make a comment about how he never make mistakes, like he always does. This was really bad.

"Look, we might be stuck in each others' body, but hey, could be worse," he tried again and this time, he saw the detective smiled slightly, but it vanished almost instantaneously.

"I was so stupid," Sherlock whispered, barely audible and voice slightly breaking, "and I should have known that there could have been complications in which I could neither fixed, nor solved. I just... I'm just too daft to admit that I could be...wrong."

A silent pause.

"Last night, I saw some of your older memories," John started, but hesitated a bit, and then resume, "Look at me."

The detective turned his head painfully and stared up into the doctor's steady eyes, seeing John through the shell of his former body.

"You are not alone," John said determinedly, "and whatever happened was in the past. But today, tomorrow, and so forth, just remember that I am here and that you are not alone. We got into this mess together and should we never get out, then that's too bad. But don't think for a second that you have to do everything on your own."

They stared for a long moment, then Sherlock sighed, resting his (_John's_) head of John's (_Sherlock's_) shoulder.

"Thank you," he said, closing his eyes, "Don't think you're alone on this battlefield either, soldier." And with that, he fell asleep. Soon after, John did as well.

* * *

Morning came quietly.

When Sherlock woke up, the first thing he saw was John resting his head on his (_his!_) shoulder, sound asleep. He looked at the doctor hungrily from his dark blond cut to his tough hands that had killed many, yet mended as well._ We're back to ourselves._

Sherlock's cellphone rang and when he looked at the caller id, he sighed warily. _What now?_

"What do you want, Mycroft?" he said tiredly and John stirred a bit.

"Oh, just to let you know that it was four hours, not one. Pardon my blunder," Mycroft gave a chuffed reply, not feeling guilty at all for deceiving his little brother one too many times. Sherlock stayed quiet for a moment.

He reflected on these past four days (if that included before, during, and after the experiment, that is) and back to his initial articulation that he had uttered to both the doctor and the detective inspector, which he had been proven wrong, very wrong. For John's 'funny, little brain' was certainly not boring (_not sure about Lestrade's though, but will probably not dig deeper into that area_) and it changed Sherlock in a way that could not be written (well, that is, to it's full extent, of course).

The Sherlock 'before' was different, much different from the Sherlock 'during' and the Sherlock 'after.' A source of error that he had not foresaw, but one that he certainly did not regret either. The end results were both meaningless, yet significant at the same time, both for different reasons. But by now, Sherlock cared not that he had been proven wrong to himself. He was glad.

"Thank you," he replied finally and hung up. Mycroft smiled and pocketed his phone. _Anytime_.

John finally woke up and found himself looking up at Sherlock's (_Sherlock's_) face, which was looking down at his.

"Thank god, I was beginning to grow tired of looking at my own face," he said simply and the detective chuckled, "Welcome back."

Sherlock leaned down and kissed him lightly. It was soft and sweet, but as he began to pull away, John swiftly grabbed the back of his head and held him in place, which was surprisingly fast for someone who had just woken up.

"I'm not done with you yet, detective," he breathed huskily, lips still slightly touching. Sherlock shivered unconsciously and smiled. He pulled John closer and deepened the kiss. Mouth slightly parted like before, the doctor tested his tongue along the inner rim of the detective's lips before meeting his tongue. Sherlock groaned, his hand trailing the back of John's spine downwards. John pulled away suddenly and smirked, "That's more like it."

"You are very cruel, do you know that?" Sherlock pouted, breathing heavily.

"And a damn good kisser, judging by your increased heart rate, heavy breathing, and amorous behaviour. Actually, it was just plain obvious, but I can give you a list of observations if you like," John deduced with a smug smile.

"Cheeky bastard," he retorted, "I rather you show me how it's done."

"I just did."

"So what now? Tea?"

"Not from you."

John laughed teasingly and snogged his partner properly once more.


	17. Epilogue

_Mycroft logged the final entry of his very own experiment and closed the booklet. __**Just as planned. No complications, no errors, perfect. Sherlock should learn a thing or two from me, but he'll probably delete it all**__, he thought and chuckled to himself, __**I should do this more often**__._

_The elder Holmes walked out to the black car and left his office for the day. He will not be spying, nor eavesdropping for the time being. The booklet sat on his desk in a very proper manner, much like its owner. Even the experiment's name was neatly written in bold cursive on the cover:_

_**Operation Mind Switch**_

Sarah Sawyer haven't heard from her boyfriend for about a week now. Having enough of asking around and trying to call for the tenth time, she decided to go to his flat, even if it meant disturbing whatever case they were working on at the moment. As she stood outside and raised her hand to knock, the door opened and she saw Sherlock standing there expectedly.

"He's gay and taken," Sherlock said before she could even utter a word.

"What? Taken? By who?" Sarah's eyes widened, her face full of surprise and confusion.

"Me, of course. Good day." And upon that assertion, Sherlock shut the door with a twist of his wrist and a _bang._

_Fin_

* * *

**A/N: **Wow, that was a long ride, almost three times longer than I had expected. Haha. Thank you guys so much for your comments and even simply just for giving this fic a chance. It had been a blast. Please let me know what you thought of the story and again, thank you for making it to the end of this journey. Have a nice day!


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